Vehicles, such as automobiles, may include equipment for protecting passengers from the impact of collisions, for example, safety belts, airbags and energy absorption mechanisms. However, it is currently difficult to provide adjustments in all of this equipment for differences in certain collision conditions, such as the magnitude and direction of a force applied to an airbag that varies due to the size of occupants and/or the speed of a vehicle may be travelling, in mass-market passenger vehicle design. By way of example, typical current airbags are designed to inflate to a set pressure determined with respect to preferred absorption performance at a relatively high test speed, and thereby only provide a single stiffness for all collisions. As such, that stiffness may not be optimized for impact events involving relatively smaller forces, e.g. relatively low speed impact events. Moreover, current mechanisms for actively adjusting deployment of equipment such as airbags, e.g. to provide variable stiffness performance under varying conditions, suffer from drawbacks including their complexity and cost.